OK, I need to upgrade my graphics card, I believe this one is on its last hamster, it has done me well (about 4 years service) but i do think its time to upgrade
i am currently running

amd athlon x2

lol

no i am running
amd fx-8350
gigabyte GA-990FXA-UD5 rev3.1
16gig of ddr 3 ram
sound blast x-fi
850 watt coolermaster psu

and finally a nvidia gtx 760 (evga)

money is at a premium at the moment but I know I can afford either
MSI GeForce GTX 1080 ARMOR OC 8GB GDDR5X Graphics Card (or similar)
or
the nvida gtx 1070

does anyone have any advice or recommendations (i maybe waiting for it to come with a free game)

I did some looking not long ago and found that if and when I can afford it I will go with the 1080. The 1070 had mixed reviews but looks like all issues got solved and the 1080 was all good.  In my case since I have the luxury of waiting I hope a new card comes out and the price on 1080 comes down. Not your situation I guess. Also both those cards fit my case and present power/cooling will be OK.  I run an Nvidea 960 Now which does all the present games,  so I am 3 ish cards behind......

Yes the 1080, for one thing if you ever decide to sli you can't with the 1070.

While the 1070 is strong, the 1080 is totally worth it in comparison!  1080 gets my vote as well.

P.S. - I would like to say that I love EVGA.  They handled my RMA quick and easily, so I trust them a lot now.

1080, no doubt

what resolution are your playing at, if 1080p save your money and get a gtx 1070 heck even a gtx 1060 will crush 1080p unless you want 120+ fps at all times, or even gtx 1070 TI which will be out soon(before the holidays).  If you plan on buying a new 1440p monitor or higher then go with gtx 1080.  BTW your CPU will bottleneck both the 1070 and 1080 at anything lower than 1440p.